Various electrical power distribution systems have been suggested heretofore which permit the selective positioning of electrical fixtures, such as lamps, at various locations along a track. The track has conventionally taken the form of an elongated metallic rail having interior webs which define ducts in which elongated electrical conductors are supported in insulated relation to the rail, and which further define support channels in spaced relation to the ducts cooperating with quick-release lockable adaptors arranged to mechanically and electrically secure the fixtures to the rail at desired locations.
In our copending application Ser. No. 462,920 filed Apr. 22, 1974 for Electrical Contact Rail, now abandoned, we have described a modified power distribution system particularly adapted for single-phase operation, which employs rail and adaptor components of comparatively small size, but which nevertheless assure that the certain minimum spacing between conductors specified by pertinent safety codes is maintained. The arrangement described and claimed in said copending application includes an elongated metal rail provided with interior webs defining elongated ducts containing insulating inserts which support elongated electrical conductors facing the interior of the rail, and which further define channels adapted to position an insertable adaptor with the adaptor contacts in engagement with the rail conductors; and the desired size reduction is achieved by providing one of the rail support channels with a stepped configuration cooperating with a complementarily step-shaped supporting clip on the adaptor, and by further providing the rail with an elongated grounding conductor which is inclined relative to the longitudinal center plane of the rail and which has one contact surface facing the interior of the rail and another contact surface facing the exterior of the rail.
In systems of the general type described, it is sometimes desirable to replace the contact rail, or to supplement the contact rail, by use of a plug-type receptacle mounted on the wall or ceiling and designed to receive a single adaptor which supports, and provides energization for, an electrical fixture at the specific location of the receptacle. Receptacles suggested for such use in the past have been arranged to receive the relatively large size adaptors which have been employed in prior art contact rail systems and, due to their resultant relatively large dimensions, such prior art receptacles are not capable of being used with the smaller size adaptors described in the aforementioned copending application. It is accordingly the primary object of the present invention to provide a new form of receptacle which can be used in place of, or as a supplement to, a comparatively small-sized contact rail, wherein the receptacle is constructed of a few easily mounted parts which are comparatively small in dimension and which can be manufactured at comparatively low cost, and wherein the receptacle is designed to receive and properly cooperate with such a smaller sized adaptor.